Existing motorcycle fairings are designed to decrease the negative effects of aerodynamic drag upon the motorcycle and rider, thereby increasing, speed, efficiency, and/or rider comfort. However, all existing fairing types (prior art) suitable for public ‘road legal’ use are only marginally effective in achieving these goals owing to compromises made in aerodynamic efficiency, in order to accommodate turning of the motorcycle. As the purpose of the new invention is to dramatically overcome the aerodynamic limitations of existing fairings, but in a design also suitable for practical, everyday use—it is necessary to first describe the types of prior art in existence. These fairing types mostly fall into two general categories, both of which encompass motorcycles designed for use on hard, smooth, street or track surfaces. The first general category will be identified as ‘road legal’, and which will contain motorcycle frontal fairings designed for legal use on public roads. The second general category will be identified as ‘specialty fairings,’ and will describe motorcycle fairings designed for competitive sport racing; speed record attempts; and fuel, efficiency, and general research testing. A third type of fairing has been proposed by this inventor, in patent application Ser. No. 11/653,452 filing date Jan. 16, 2007, which is an alteration of elements of the first two types, but which is not in substantial use as of the date of this specification. Therefore the following discussion will most emphasize the first two fairing category types noted above, with a discussion of this third type to follow.
Beginning with the road legal category of motorcycle fairings, the types of frontal fairing found on motorcycles designed for legal use on public roads can be generally described as belonging to one of two types, dependant upon the location of the points of attachment used to secure the fairing to the motorcycle. These two attachment-point described types of categories can be described as either: in the first instance—the fork-mounted type; and in the second instance—the frame mounted type. In regard to second type, the frame mounted type has been common in the post World War II period, and the fork mounted type is most probably nearly as old as the existence of the motorcycle itself, having been a natural evolution from the first rudimentary motorcycle windshields developed early in the twentieth century.
In the fork-mounted type, the fairing is generally less expensive, more simple, smaller, and most notably—the fairing is attached to the front forks, and/or handlebar in a rigid fashion, as such as when the motorcycle operator executes a turn by rotation of the handlebar, this type of fairing turns laterally in concert with the front forks, handlebar, and front wheel assembly; and independently of the main frame of the motorcycle comprising the engine, drive assembly, rear wheel, fuel tank, etc. Although the fork-mounted type does provide some marginal degree of wind protection for the rider, the overall value of the fork-mounted fairing is negligible in terms of decreasing aerodynamic drag, and thus increasing efficiency and performance. Because the fork-mounted fairing is not affixed in the forward-most position on the motorcycle, but rather is located above and behind the exposed front wheel, brake(s), fender, headlight, and fork tubes—which together comprise the actual leading edge of the motorcycle into the oncoming air stream—the oncoming airflow encountered by the fork-mounted fairing is already turbulent, ‘rough’ air. Therefore any opportunity to establish a smooth, or laminar flow of air around such a relatively rearward mounted type of fairing are lost. Further, as the distance between the rear portion of the fork-mounted fairing and the upper torso and head of the rider is a relatively large one—the resultant gap leads to yet more turbulent air which not only reduces the efficiency and performance of the motorcycle, but also increases the buffeting, noise, and general discomfort experienced by the rider.
The second general type of fairing used on road legal motorcycles—the frame-mounted fairing, is attached rigidly to the main frame of the motorcycle, and thus when the motorcycle operator executes a turn by rotation of the handlebar, the fairing does not turn laterally with the front forks, handlebar, and front wheel assembly. As in the fork-mounted type described above—the principal functions of the frame mounted fairing are to decrease the aerodynamic drag and its effects upon the motorcycle and the rider/operator, thus increasing the performance and efficiency of the motorcycle, while also increasing the wind and weather protection for the rider.
Unlike the handlebar-mounted type fairing which is mounted above and somewhat behind the leading edge of the front wheel—the frame-mounted type, although also located above and behind the leading edge of the front wheel—the frame mounted type additionally encloses some of the lower portions of the main frame of the motorcycle, often including the engine, transmission, and portions of the engine air intake and exhaust components.
However, like the handle-bar mounted type, the frame mounted type also does not enclose the aerodynamic leading edge of the front wheel, forks, and brake assembly which encounter the oncoming headwind. Nor does either of these types cover more than a very small fraction (if any at all) of the area of the total lateral diameter of the front wheel and tire assembly, This lateral area being the total circular area of the combined front wheel assembly visible when said assembly is viewed from either side of the motorcycle.
Although in most cases a fender (also known as a mud-guard) does cover a portion of the exterior circumference of the front wheel and tire assembly, the portion of the total lateral area of front wheel and tire assembly that is covered by the fender is marginal (if any at all), and if any aerodynamic drag reduction does result from the shape of the fender, it is generally incidental to the intended primary function and design of the front fender which is to protect the motorcycle engine components, and rider from foreign objects and water propelled upward as the result of the rotating front tire's interface and contact with the road surface, and foreign object thereupon. Although in a few instances of road legal motorcycles, some fenders or mud-guards have been designed with some very small degree of aerodynamic efficiency in mind, in no case are the fenders an integral part of the fairing itself, but rather a completely separate part or component.
Although generally covering a larger area of the motorcycle, than the fork-mounted type; as the frame-mounted type of fairing does not extend to, nor cover the front wheel, brake, fender, and fork assembly—thus leaving these latter components again to act as the leading edge of the motorcycle into the oncoming air stream. Therefore although the frame-mounted type of fairing may provide a somewhat decreased level of aerodynamic drag when compared with the fork-mounted type, or the motorcycle sans any fairing—like the fork-mounted type—the rearward leading edge of the frame-mounted type again results in the airstream that encounters the fairing to be a turbulent, rough airflow that again makes smooth or laminar airflow over the fairing virtually impossible. Although it is true that the frame-mounted type does generally provide better aerodynamic drag reduction as compared to a fork-mounted type, or motorcycle without any fairing at all—it is still only a marginally efficient aerodynamic shape due to the fact that the leading edge of the entire vehicle is comprised of the rough and irregular shapes and edges of the front wheel, brake, fender, and fork assembly. In terms of aerodynamic efficiency then, the shape of the leading edge of any airfoil is critical—thus the rough and irregular shapes of the leading edges of the motorcycle, cannot be efficiently overcome to any large degree, no matter how smooth the frame-mounted fairing exists over the medial and posterior parts of the motorcycle. In other words, the front wheel, brake, fender, and fork assembly of a motorcycle must be wholly or substantially enclosed to attain the most of aerodynamic drag reduction benefits.
The frame-mounted type fairing is also further designed to allow for the flow of the oncoming airflow to contact the engine fluid cooling units, in the form of both the coolant radiator, and/or the engine oil cooler, at an angle of attack which is directly perpendicular to the direction of travel of the motorcycle and the resulting oncoming airflow. Although this does allow for maximum cooling efficiency of the radiator and/or engine cooler, it also dramatically the aerodynamic drag effect upon the vehicle, thus reducing overall efficiency and performance. An analogous example in nature which approximates the frame-mounted fairing would be the salmon. If one envisions a healthy salmon traveling up a river into the current, one can easily appreciate the smooth, efficient sleek design of the body of the fish. If one were to then imagine the salmon swimming up the same stream into the same current—but now with its mouth wide open—one can appreciate both the effect upon the progress of the fish (or the similar shape of a motorcycle equipped with a frame mounted fairing), when the very efficient latter portion of the body of the fish (or said motorcycle), is largely negated by the blunt open mouth.
Turning to the Specialty category of motorcycle fairings as opposed to the road legal types described above—these special types of fairing can be differentiated and categorized into two basic types, with the determinate criteria not being the method of attachment (as is the case with the road legal type) but rather by the degree or amount of the motorcycle which is either partially or fully enclosed by the respective fairing type.
The first of these two types is commonly known as the streamlined, or fully enclosed type. This type of fairing usually is constructed as a single fully enclosed body, which resembles, and is constructed similarly to that of a modern low drag/high speed aircraft fuselage. In this type, the outer surface or skin of the fairing is generally cylindrical in shape, with only small openings at the front and rear wheel locations of the motorcycle to allow for minimal, vertical protrusion of the front and rear wheels to a distance minimally sufficient for clearance of the lower main body of the fairing from the ground surface. Additionally, small holes or openings may exist for engine cooling, intake, or exhaust functions. A small aircraft style enclosed canopy, or aerodynamically designed open-topped windscreen is usually also incorporated into the fairing's upper surface, to allow the operator a visual portal to control the vehicle, while also minimizing frontal surface area. This type of fairing is used almost exclusively for competitive speed record attempts, wherein the vehicle is not required to make any significant turns, but rather travel only in a straight line, at the highest possible speed. As the design of this type of fairing is designed for maximum aerodynamic reduction, but is not concerned with the turning necessary of practical everyday transportation, it can be, and is made as narrow as possible, with the rider being fully enclosed within the fairing after entering the vehicle through a door or moveable panel, which is located on the top or side of the fairing. Therefore although this type of fairing is truly very aerodynamically efficient, the inability of the front wheel to turn laterally, to any practical degree, combined with the inability of the rider to extend his legs and feet outside the vehicle when coming to a full stop—render this type of fairing essentially useless for public road or practical use.
The second of these special fairings, is commonly known as the dustbin fairing. The name of which traces its origin to the decade of the 1950's, wherein the fairing's appearance (when viewed from the side), strongly resembled the shape of the common dustbin with handle, used domestically as a household tool in conjunction with the common broom, to remove floor sweepings. The most apparent, and defining characteristic of the dustbin style fairing, it the shape of the front of the fairing, which substantially encloses the front wheel and tire assembly, with the fairing attached. This type of fairing was used from approximately 1953 until 1956 in closed course motorcycle road racing, principally in Europe, and most notably in Grand Prix motorcycle racing circuit, until the dustbin was banned in European competition by the sanctioning body of those events. In addition to the substantial enclosure of the front wheel and tire assembly, the dustbin fairing was attached to the motorcycle by attachment points located on the main frame of the motorcycle, and protruded forward from the main frame to enclose most of said front forks, wheel and tire assembly. As such the dustbin fairing was not directly attached to the front forks or handlebars of the motorcycle, but rather frame mounted in the same fashion as the previously described road legal frame-mounted type.
Although this configuration allowed some lateral turning of the front forks and wheel and tire assembly by laterally rotating the handlebar, such turning was limited to only a few degrees of rotation to either the left or right, as the enclosed wheel and tire assembly, as well as the handlebar and front forks, would come into almost immediate contact with the interior of the sides of the frontal portion of the fairing encompassing the front wheel, which severely limited the ability for the rider to execute any turn of more than a few degrees, thus rendering the motorcycle equipped with the fairing to be extremely difficult to use for any purpose other than competitive road racing, and thus inconvenient and wholly unsuitable as a means of practical transportation. Further in an effort to provide these dustbin fairings with this small degree of ability to turn, a large opening or hole would be incorporated to allow the front wheel to turn laterally. Although this did marginally allow for some ability to turn the motorcycle laterally—the opening itself allowing such movement, was itself a deleterious to the dustbin design, as the opening greatly increased drag and turbulence on the under side of the fairing, as smooth, laminar airflow over the nose of the fairing became turbulent, rough air upon encountered the large gap found to either side of the front wheel, brake, fender, and fork assembly, on the bottom of the fairing.
A final characteristic of the dustbin fairing which is notable, was the effect of cross winds upon the stability of a dustbin equipped motorcycle, especially at high speed. As the dustbin fairing's surface area extended forward of that of the non-dustbin frame-mounted, fairing—the location of the center of pressure resulting from a crosswind blowing laterally from a perpendicular direction upon the dustbin fairing, would more forward, than that of the location of the center of pressure on a non-dustbin motorcycle fairing. However, because of the relatively light weight of the dustbin fairing in relation to the combined weight of the motorcycle and rider, a the lateral aerodynamic center of pressure is moved forward, while the center of mass of the total weight of the vehicle did not move forward to a corresponding amount. Therefore the front of the dustbin fairing equipped motorcycle, was said by contemporaneous accounts to have had an increased tendency to be turned away from the intended straight-line direction of travel, in a lateral fashion, in direct reaction to, and as a direct result of the crosswind imparting a moment of force upon the more forward located, lateral center of aerodynamic pressure found in the forward extending dustbin type. This last characteristic resulted in the dustbin style fairing being given a reputation, as least as far as historical accounts go, as being harder to control in windy conditions than either non-dustbin style fairing equipped motorcycles, or motorcycles without any fairings. Thus from the historical reports from the decade of the 1950', the dustbin type fairing was generally reported, and thus thought to be more dangerous to use in racing conditions in any type of intemperate weather, which, was cited as a major contribution to its exclusion from competitive motorcycle racing in Europe in 1957. However, the principal competing motorcycle manufacturers of the period, may have also had additional, unrecorded reasons for the elimination of the dustbin fairing, owing to both production costs, and aesthetic considerations.
The third general type of fairing which is currently the subject of patent application Ser. No. 11/653,452 and submitted by this inventor on Jan. 16, 2007 is the Aerodynamic Articulated Motorcycle Fairing, which as described in that patent application is a combination of, and improvement upon some of the characteristics of both the frame and fork mounted fairing types. The purpose of that proposed invention, is to combine the aerodynamic advantages of the dustbin style faring with the ability to turn the front wheel as found on a conventional motorcycle. That invention is designed to achieve those ends by allowing the frontal fairing section enclosing the front wheel to turn independently of the frame mounted section by arranging the interface of the two fairing sections, and the frontal fairing rotation, to be arranged such a way as to be perpendicular to the axis of rotation of the front wheel and fork assembly.